The best replacement for enzyme is catalyst.

The best alternatives to enzyme are rated as following:
★★★★★  catalyst
★★★★  protein
★★★★  hormone
★★★★  substrate
★★  coenzyme
★★  substrate concentration
★★  probiotic
★  antibody
★  ph
  inorganic catalyst
  holoenzyme
  acid
  non biological catalyst

Your alternative for enzyme is not listed? Suggest!
Speaking about enzyme, one probably shouldn't forget about substrate.

Other search terms related to enzyme and their ratings are:
★★★★★ substrate
★★★★★ cofactor
★ hydrogen peroxide
ase
protease
h2o2
You have in mind a companion for enzyme and it is not yet here? Propose!



Google Trends

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enzyme
catalyst
protein